For articulating the boom to the turntable, the two solutions shown in FIGS. 1 and 2 are known. FIG. 1 shows a double-shear bearing of the boom 1 on the turntable 2. For this purpose, two bearing plates 3 with corresponding bearing points 4 for the bolts 5 are provided on the turntable 2. The bolt 5 connects the bearing points 4 on the bearing plates 3 with the bearing tube 7 on the boom 1 which here is shown as monoblock boom 6.
This design has the advantage that the boom fabricated as a closed box is extremely torsion-resistant. When the system is designed for greater loads, the double-shear bearing however leads to a number of disadvantages, such as for example to a long, heavy and hence hardly handleable bolt, to an increasing deflection of the bolt, and to a high bearing stress.
Furthermore, the four-shear bearing shown in FIG. 2 is known, in which two parallel bearing plates 3 each are provided to the left and to the right on the turntable 2, which each include bearing points 4 for one of the two bolts 5. The boom foot of the boom 1 is bifurcated far apart for articulation and includes two bearing sleeves 7 which via the bolts 5 are connected with the respective bearing points on the left and right bearing plates, respectively. This leads to the fact that short, lightweight and correspondingly easily handleable bolts can be used, which in addition have a low bolt deflection. Furthermore, the bearing stress is correspondingly lower. What is, however, disadvantageous in this solution is the lower torsional stiffness of the monoblock foot 6 due to the design being bifurcated far apart.
Despite the disadvantages of the respective solutions known for decades, an articulation which combines the advantages of the two articulations and avoids their respective disadvantages has not been found so far.
It is the object of the present disclosure to provide an improved articulation of a boom on the basic unit of the implement.
In accordance with the present disclosure, this object is solved by an implement comprising a boom which is pivotally mounted about a horizontal axis via a bolt connection on a basic unit of the implement. According to the present disclosure, the boom now is mounted on the basic unit via three bearing plates with corresponding bearing points for the bolt connection. Such three-shear bearing via three main webs combines the advantages of the double-shear and the four-shear bearing, without having its disadvantages.
Thus, after decades of stagnation in the field of the articulation of booms, the present disclosure for the first time provides a fundamentally improved new conception of such an articulation.
Advantageously, the bolt connection is effected via at least two bolt elements. This provides for using short and correspondingly lightweight bolts, which correspondingly are easily handleable and have a low bolt deflection.
Advantageously, the bolt connection is designed such that the at least two bolt elements each are inserted from the outside to the inside. In particular, the two bolts are put through the respective bearing points of the two outer bearing plates from outside and are secured at the two outer bearing plates.
When two bolt elements are used for the bolt connection, the same advantageously support on the middle bearing plate with their inner ends. The middle bearing plate therefore advantageously includes a correspondingly dimensioned bearing point. Advantageously, the bearing point on the middle bearing plate is prolonged on both sides beyond the thickness of the bearing plate.
Alternatively, the bolt connection also can be effected via three bolt elements, with the middle bolt element supporting on the middle bearing plate. Here as well, the bearing point on the middle bearing plate therefore advantageously is dimensioned correspondingly and furthermore advantageously is prolonged on both sides beyond the thickness of the middle bearing plate.
The middle bolt element can floatingly be mounted on the middle bearing plate and in turn solely be secured via the outer bolt elements, which are secured on the outer bearing plates. Alternatively, however, securing the middle bolt element on the middle bearing plate also is conceivable.
In the present disclosure, the bolt elements furthermore can be connectable with each other via plug connections. This provides for a positive connection of the bolt elements with each other. In particular, this allows a centering and/or support of the individual bolt elements on each other.
Advantageously, adjacent end faces of the bolt elements include a corresponding protrusion or a corresponding cutout, so that the protrusion on the one end face can be pushed into a cutout on the other end face.
Particularly preferably, such plug connections are employed when using three bolt elements, so that the middle bolt element is connectable with the two outer bolt elements via the plug connections.
According to the present disclosure, a bearing point furthermore can be provided on the middle bearing plate for articulating an energy recovery cylinder. The middle bearing plate thus allows a particularly easily realizable articulation point for the energy recovery cylinder, which advantageously extends from this bearing point towards the boom. The bearing point for the energy recovery cylinder can be arranged below the bearing point for the articulation of the boom.
Furthermore, on the outer bearing plates there can each be arranged bearing points for the articulation of hydraulic cylinders for moving the boom. The same substantially can be designed as known from the prior art, for which purpose corresponding additional bearing plates advantageously are provided, in order to each provide for a double-shear articulation of the two hydraulic cylinders.
Advantageously, the three bearing plates of the implement according to the present disclosure extend upwards in vertical direction from a support structure of the basic unit. In particular, the three bearing plates can be aligned parallel to each other and/or extend in longitudinal direction of the implement. In particular, the articulation axis is vertical to the three bearing plates.
Furthermore, the bearing plates and a supporting frame of the basic unit can form a welded construction. In particular, the bearing plates each are steel parts which are welded to a supporting frame of the basic unit or form part of such supporting frame.
The boom foot of the implement according to the present disclosure likewise can be designed as a welded construction. In particular, this is a closed box construction in accordance with the present disclosure.
Like in a four-shear bearing, the boom foot advantageously includes two bearing bushings which are welded to the box construction and through which the bolts extend for connection with the three bearing plates. Other than in a four-shear construction, the two bearing bushings can however be arranged very close to each other, so that the monoblock foot is bifurcated only little and has a correspondingly higher stiffness.
Advantageously, the distance between the two bearing bushings on the boom is smaller than their respective length. This results in a correspondingly high stability of the boom.
This dimensioning also is reflected in the dimensioning of the bearing points of the three bearing plates. In particular, the free distance between the respective bearing point on one of the outer bearing plates and the bearing point on the middle bearing plate is greater than the width of the bearing point on the inner bearing plate.
The novel articulation of the boom according to the present disclosure particularly advantageously is employed in implements with an undercarriage, with a traveling gear and an uppercarriage arranged on the undercarriage about a vertical axis of rotation, wherein the boom is articulated to the uppercarriage. Furthermore, the boom can carry a working tool. It can also be provided that the boom is movable via hydraulic cylinders.
In particular, the implement according to the present disclosure can be a mobile implement, for example a construction, earth-moving and/or material-handling machine. In particular, the implement according to the present disclosure is a hydraulic excavator.
Beside the implement, which consists of basic unit and boom, the present disclosure furthermore comprises a basic unit for such implement. Such basic unit includes the three bearing plates according to the present disclosure.
Advantageously, the basic unit is constructed such as it has already been described above.
Furthermore, the present disclosure also comprises a boom for an implement according to the present disclosure. The boom includes two articulation bushings which can be articulated to a basic unit of an implement according to the present disclosure via the three-shear bearing according to the present disclosure.
The present disclosure will now be explained in detail with reference to exemplary embodiments and drawings.